Darwin's Finches

Abstract

Darwin's finches are a prime example of adaptive radiation and of evolution in action. Beak size of these equatorial bird species repeatedly changed within two decades as a response to environmental changes during El Niño conditions.

Keywords: birds; equatorial; evolution; beak size; adaptive radiation; tropic

Figure 1.

Darwin's finches show most extreme differences in beak size and shape. The Warbler finch (a) has the smallest, the Large ground finch (b) the largest beak. Medium ground finches (c, left) and Small ground finches (c, right) are typical seed eaters and have graded differences in beak size. Photographs © Martin Wikelski.

Figure 2.

Phylogram of Darwin's finches based on microsatellite length variation. Birds are drawn at approximately actual size. Horizontal branch lengths represent genetic distance. Names are given in full in Table 1. The beak shapes of Darwin's finches are compared to different types of pliers. Redrawn from Petren et al. and Bowman .

Figure 3.

Frequency distributions of beak depths of three species of adult male Ground finches (Geospiza) on the two islands of Santa Cruz and Daphne. Note that beak sizes are different between the species on Santa Cruz and that G. fortis beaks on Daphne are smaller than on Santa Cruz. Redrawn from Grant .

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References

Boag PT and Grant PR (1984) The classical case of character release: Darwin's finches (Geospiza) on Isla Daphne Major, Galápagos. Biological Journal of the Linnean Society 22: 243–287.

Bowman RI (1961) Morphological differentiation and adaptation in the Galápagos finches. University of California Publications in Zoology 58: 1–302.

Grant BR and Grant PR (1989) Evolutionary Dynamics of a Natural Population. The Large Cactus Finch of the Galápagos. Chicago: University of Chicago Press.

Grant PR (1986) Ecology and Evolution of Darwin's Finches. Princeton: Princeton University Press.

Grant PR (1993) Hybridisation of Darwin's finches on Isla Daphne Major, Galápagos. Philosophical Transactions of the Royal Society of London B 340: 127–139.

Grant PR and Grant BR (1995) Predicting microevolutionary responses to directional selection on heritable variation. Evolution 49: 241–251.

Lack D (1947) Darwin's Finches. Cambridge: Cambridge University Press.

Petren K, Grant BR and Grant PR (1999) A phylogeny of Darwin's finches based on microsatellite DNA length variation. Proceedings of the Royal Society of London B 266: 321–329.

Vincek V, Ohuigin C, Satta Y et al. (1997) How large was the founding population of Darwin's finches? Proceedings of the Royal Society of London Series B Biological Sciences 264: 111–118.

Further Reading

Weiner J (1994) The Beak of the Finch. New York: Vintage Books, Random House.

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How to Cite close
Hau, Michaela, and Wikelski, Martin(Apr 2001) Darwin's Finches. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0001791]